Synthesis, platinum(II) complexes and structural aspects of the new tetradentate phosphine cis,trans,cis-1,2,3,4-tetrakis(diphenylphosphino)cyclobutane

Unprecedented conformational modulation of the efficiency of luminescence in Ru(II) bipyridyl complexes containing a bis(bidentate) phosphine

“…Furthermore, two different diastereoisomers occur for 3 and 4: Fig. 1 shows the K/MPPP form for 3 and its K/MMMP counterpart for 4 [1,5], where of course also their mirror images are present and a detailed discussion will be reported elsewhere. It is important to note that 3 and 4 consist of pure diastereoisomers leading to unequivocal photophysical properties.…”

“…This leads to lowest-lying triplet excited states on comparable remote ligands and is important for the basic understanding of next-generation dye-sensitized solar cells [4]. However, though the bis(bidentate) phosphine dppcb recently designed in our laboratory [5] backbone (see Chart 1), a fine-tuning of the efficiency of luminescence in mono-and bimetallic combinations of dppcb with [Ru(bpy) 2 ] 2+ is possible for the first time due to steric constraints. In this work, proof positive is presented regarding the preparation of a RuP 2 N 4 phosphine complex of Ru(II) containing a saturated backbone with an extended excited state lifetime at room temperature, which is measurable for the first time due to an enhanced luminescence.…”

“…1) [13]. Interestingly, the chirality of 3 and 4 is ''frozen-in'' at ambient temperature, since the 31 P{ 1 H}NMR signals corresponding to axial and equatorial moieties, respectively, are well-resolved and sharp [5]. Furthermore, two different diastereoisomers occur for 3 and 4: Fig.…”

Asymmetric [2+2] Cycloaddition of (E)‐2‐(Diphenylphosphanyl)styrene Promoted by a Chiral Metal Template

“…Similarly, the enantiomeric products (R)-2 and (R)-3 can be obtained in the same ratio of 6:1 when the equally accessible complex (R)-1 is used as the chiral metal promoter for the cycloaddition reaction. As related transition-metal-assisted thermal or photodimerizations of vinylphosphanes and phospholes have been reported to proceed via a stepwise biradical mechanism, [5,16] it is possible that the present chiral organoplatinum-template-promoted dimerization of (E)-2-(diphenylphosphanyl)styrene also follows such a biradical pathway. However, a stepwise addition involving zwitterionic intermediates and a concerted pathway cannot be ruled out.…”

“…Recently, it has been reported that the intramolecular [2+2] photochemical dimerization of trans-1,2-bis(diphenylphosphanyl)-ethene can be promoted efficiently by platinum and palladium ions. [5] The resultant tetradentate phosphane and other phosphane ligands with the cyclobutane backbone have been successfully applied to many metal-catalyzed reactions. [6] Over the years, chiral cyclometalated-amine complexes have contributed significantly in many aspects of synthetic chemistry.…”